硒半胱氨酸和硒胱氨酸的间接气相色谱测定──溴化氰－气相色谱法

The Determination of Selenocysteine and Selenocystine by CNBr-Gas Chromatographic(GC) Method

将硒半胱氨酸（ＳｅＣｙｓＨ）甲基化，对硒胱氨酸（ＳｅＣｙｓ）需还原后再甲基化。它们生成的甲基硒半胱氨酸（ＣＨ＿３ＳｅＣｙｓＨ）能与溴化氰（ＣＮＢｒ）发生专一性反应，定量生成的硒氰酸甲酯（ＣＨ＿３ＳｅＮ）可用气相色谱法（ＧＣ）测定。此法简称ＣＮＢｒ－ＧＣ法，检测限４×１０￣（－８）克ＳｅＣｙｓ，准确度８９．５％，相对标准差１２．１％，非含硒氨基酸不干扰。此法适于样品中微量硒氨基酸（硒蛋氨酸ＳｅＭｅｔ，ＳｅＣｙｓＨ和Ｓｅｃｙｓ）的测定。

method for the determination of selenocysteine(SeCysH)and selenocystine(SeCys)by indirect GC hasbeen established. The principles of this method are that SeCys is converted to methyl-selenocysteine(CH_3SeCysH)by reduction and methylation, and then CH_3SeCysH specifically reacts with CNBr to formCH_3SeCN which can be determined by GC, This method is called CNBr-GC method.The detection limit andaccuracy of this method are 4.0×10￣(-8)g and 89.5%respectively.The determination of SeCys and SeCysH wasnot interfered with sulfur-containing amino acids, It can be used for the determination of SeCysH and SeCys inbiological samples without further hydrolysis.